Floating thickener



Feb. 10, 1953 P. A. CURTIS FLOATING THICKENER 2 SHEETS-SHEET 1 FiledDec.- 27, 1948 Feb. 10, 1953 I P. A. CURTIS 2,627,978

FLOATING THICKENER Filed Dec. 27, 1948 2 sHEETs sHEET 2 upa/o /0 IN VENTOR.

ATTD R N EYB Patented Feb. 10, 1953 UNITED STATES PATENTiOFFICE FLOATINGTHICKENER Paul Aivle Curtis, Lakeland, Fla.

Application December 27, 1948, Serial No. 67,511

(Cl. 21u-55) Claims.

The present invention relates to improvements in liquid separation andpurifying apparatus, and more particularly to hydroseparators,thickeners and other types of decanting apparatus for removing sludgeand solid particles from liquids.

One object ofthe invention is to provide a liquid separation andpurifyingapparatus having radially extending rake arms which arefioatingly and buoyantly mounted to permit the arm rakes to be raisedand lowered depending upon the consistency load encountered by saidrakes.

Another object is to provide a liquid separation and purifying apparatussuch as a thickener with radially extending arms for supporting rakesfor directing the solid material toward the center of the tank and tomount said rake supporting arms on pontoons or other floats within thetank to enable the position of the rakes to be raised and lowered orcontrolled automatically depending upon the load imposed on the rakearms.

Another obj ect is to provide a liquid separation or purifying apparatusin which the ballast in the pontoons or oats is automatically controlledto raise or lower the rake arms depending upon the load imposed on therake arm driving motor units.

Another object is to provide a liquid separation and purifying apparatussuch as a thickener with a rotatable rake arm which is driven byparallel and opposite forces applied to the ends of the arms in coplanardirections so that increased horsepower ywill be developed and the powerrequired to rotate said arm will be diminished.

Another object is to provide a liquid separation and purifying apparatussuch as a thickener in which the forces applied at the outer ends of thearms is created by liquid propellers operating in a circular liquidpathway or thickener tank collection trough so that the arm is free tomove up and down depending upon the load conditions existing within thetank.

Another object is to provide a liquid separation and purifying apparatusin which the rake arms are driven by yieldingly mounted and gravitybiased traction wheels supported on the outer ends of the arms wherebysaid arms can move freely in a vertical direction depending upon.thedriving load imposed on the driving motor units.

Another object is to provide a liquid separation and purifying apparatussuch as a thickener withvpropelling units on the rake arms mountedeither within the tank or within the overflow liquid pathway surroundingthe tank. V

.Another object is to provide a liquid separation" and purifyingapparatus having a solid removal voutlet centrally arranged which iscontinuously kept clear and in an operative condition bymeans ofscrapers located on hinged sections` of the rake arms and arranged inwiping or scraping engagement with said outlet openings.

Another object is to provide a liquid separation and purifyingapparatusin which the rake arm supporting pontoons or floats areprovided with automatically operated pumps controlled by reversiblemotor units to increase or decrease the ballast within the pontoons orfioat chambers and permit said rake arm to be raised or lowered inaccordancewith the load conditions ex isting within the thick'enertanks.

Another object is to provide a liquid separating and purifying apparatusof the above-mentioned type-in which the central oat member is of an-vvnular formation and is supported on fixed rollers? engageable with theinner periphery of said annular float member to center said rakearmassembly and prevent displacement thereof. n

Other objects and advantages of the invention will become apparentduring the course of the following description of the accompanyingdrawings wherein: Y

Figure 1 is a top elevational view of the liquid purifying andseparation apparatus showing the manner in which the rake supportingarms are driven by motor propelling units aixed to the free ends thereofwith their propellers in frictional driving engagement with liquid inthe overflow trough or pathway.

Figure 2 is a diametrical cross sectional view showing the manner inwhich the rake supporting arms are buoyantly and floatingly mounted onpontoons or iioats attached to the arms.

Figure 3 is a fragmentary diametrical cross sectional view similar toFigure 2, but showing the central structure of the apparatus greatlyenlarged to illustrate various structural details such as the annularsupporting float chamber, outlet wiping scrapers and supportingfoundation construction. Figure 4 is a horizontal cross sectional viewtaken on line 4-6 of Figure 3 looking in the direction of the arrows andshowing the outlet wiping and cleaning Scrapers carried byhingedsections of the rake supporting arm structure.

Figure 5 is a fragmentary cross sectional view taken on line 5--5 ofFigure 1 looking in the direction of the arrows and showing the overflowWeir in the collection trough outlet. y

Figure 6 is a fragmentary side elevational view of another modified formof the invention showing the manner in which a yieldingly mounted motorunit is provided with a traction wheel and is arranged on the rakesupporting arm to frictionally urge a circular track on the thickenertank. r Figure 7 is a fragmentary side elevational view of a modifiedform of the invention showing a floatingly mounted friction drivingwheel on the end of the rake supporting arm in frictional drivingengagement with a circular portion or rim of the thickener tank, A

Figure 8 is a fragmentary end elevational view of the drive structureshown in Figure 7, further illustrating the manner in which the frictiondriving wheel is floatingly mounted to compensate for various positionsof said rake supporting arm.

Figure 9 is a fragmentary side elevational view of another modified formof theinvention showing a portion of the thickener tank in section and africtional driving wheel supported on the free end of the rakesupporting arm in driving engagement with the inner peripheral wall ofthe thickener tank, and

Figure is a View illustrating the electrical circuit for the motors andpump. f

In the drawings, and more in detail, there is shown one embodiment ofthe invention in Figures l to 5 inclusive, and for the purpose ofconvenience of illustration aliquid clarifying tank 5 having a slopingbottom wall 6 extends centrally and is integrated with a'well. l forminga foundation for the same. The well l is provided with a cylindricalcolumn 8 which is ared outwardly as at 9 having discharge openings It)diametrically opposed so that the sediment directed toward the center ofthe tank may be discharged through a Y connection H with the dischargeports Ill, and thence through the well to a point of discharge throughthe pipe l2. Liquid to be clarified is conducted to the well l by meansor" a pipe i3 and passes through a horizontal duct la and thenceupwardly through a stand pipe i5, where it is discharged through nozzlesl projecting through the cylindrical column 8.

The peripheral edge of the tank is provided with the usual launder I8having a discharge i9 provided with a baille or weir 2i). The tankgenerally indicated 5 is located adjacent or in a convenient location toa processing plant in which the liquid to be claried is a waste product.

Rotatably supported by the column 8 and capable of vertical movement, isa rake arm generally designated 22 and said rake arm includes radiallyextending trussed structures 23, which have their inner ends connectedto an annular iioat chamber 2li. Suitable brace members being providedto connect the arms 22 to the float, and said float includes a bottomwall 25 connected by outer and inner peripheral walls 26 and 2l. Inaddition, arcuately shaped pontoons 23 are secured to the underside ofthe rake `arm 22 to stabilize the free ends of the rake arm. The usualrakes 30 are mounted on the rake arm 22 for directing the sediment onthe sloping bottom of the tank 5 toward the central discharge outlets Iil.

In addition to the arcuately curved rakes 30, there is provideddischarge Wipers or Scrapers 3l and 32 which are secured to a hingedframe 33 pivotally connected to the lower truss structure of the rakearm as at 3d. The Scrapers or wipers 32 being arranged at an angle totravel over the outwardly flared portion 9 of the column and maintainthe discharge openings i0 in an unobstructed condition. Arms 35 aresecured to the frame 33 and extend inwardly to engage an annularlimiting stop 36 secured to the cylindrical column 8 so as to preventthe frame 33 from moving downwardly beyond a predetermined limit, butyet allowing said frames 33 to maintain their position when the rake arm22 is elevated.

The rake arm 22 is thus oatingly mounted within the tank 5, and in orderto hold the same in a centeredposition the cylindrical column 3 isprovided with a series of radially extending vertically spaced arms 38between the free ends of which is mounted guide rollers 39. The guiderollers 39 engage the inner periphery 21 of the iloat 24 and thus holdthe rake arm in position. The free ends of the rake arm 22 extend overthe launder I8 as at 40 for supporting electric motors 4l in a suspendedposition within the launder i 8 as clearly shown in Figure 6. Impellers42 are mounted on the armature' shaft of eachA motor,

and the motors are arranged to produce opposite forces .at eachend ofthe `rakearm.. Hence, the liquid overilowing the tank and into thelaunder i8 provides a liquid pathway into which the impellers 42 areoperatively received so that the propolling force of the impellel's willrotate the rake arm 22 in the direction of the arrows shown in Figure 1.

Suitable electrical conductors are provided for supplying the motors 4Iwith electrical energy, and said conductors 43 extend inwardly along theupper surface of the rake arms 22 and are provided with extensions isiwhich are connected to a common cable 45 mounted on a hinged arm d8which 1carries a pair of contacts di for engaging collector rings t8 onthe upper wall of the cylindrical column 8, Figure 3. Thus, the electricmotors :il are energized from a suitable source of electrical energywhich may be supplied to the collector rings 3S through a cable,extending upwardly through the cylindrical column 8 (not shown).

In order to vary the ballast within the annular iioat chamber 24 a gearpump 5l is mounted therein, and said gear pump is provided with a shaft52 which is drivingly connected to an electric motor 53 mounted on thetop wall of the annular iioat chamber 2G. rhe motor 53 being of thereversible type such as to enable a combined feed and discharge pipe Slito iill or discharge the ballast 5S when the pump l is operated inreverse directions. The pipe 5t extends externally of the float chamber2li and projects downwardly into the liquid in the tank 5. The liquid isdischarged or fed to the pump 5| through an opening in the casing sothat when the motor 53 is rotated in one direction, ballast will besupplied, and when rotated in the opposite direction the ballast will bedischarged. The motor 53 is adapted to be regulated by means of anoverload switch in circuit with the motors di such that when the liquidin the tank 5 is oi' a heavy consistency and the motors are loaded, themotor 53 will be rotated in a direction to discharge a portion of theballast in the tank 59 so that the rake arm will be elevated asuiiicient distance from the iioor of the tank and thereby allow themotors 4i and impellers 42 to eiectively drive the rake arm 22. When theliquid within the tank 5 is of a relatively thin consistency, the motors53 are operated in a reverse direction to cause the pump 5l to feedballast to the annular oat chamber 2. The motor 53 is electricallyconnected by a cable 'in circuit with the control switch and thence tothe cable 44 so that it will be supplied with electrical energy throughthe yielding contacts "il and conductor rings t8.

In the modified form of the invention shown in Figure 6 the liquid tank5a is provided with a launder lila and a rake arm 22a as before. Thefree end of the rake arm is provided with an extension Alla terminatingin a downwardly depending arm 51a to which is hinged a bracket 5ta as at59a. An electric motor 6ta is mounted on the bracket 58a, and has itsarmature shaft provided with a traction wheel E l a for engaging anannular track 32a on one of the walls of the launder Ia. A coil spring63a has one end in engagement with the bracket 58a and its opposite endin engagement with the extension 33a to yieldingly urge the motor andtraction wheel Sla into frictional engagement with the annular track62a.

In the modified form of the invention shown in Figures 7 and 8 the tank5b is the same as that 'shown in Figures l to 5 inclusive, and isprovided with a peripheral launder 18h likewise as before. The free endsof the rake arm 22h are provided with brackets 65th having spaced slidebearings 55h for slidably receiving a fork 51th. The lower end of thefork bib is angled slightly and terminates in spaced fork arms @8bbetween which is lournaled a rubber tired friction drive wheel lb. Apulley 'Hb is mounted en the axle shaft 72b of the wheel, and is adaptedto be driven by an endless belt 'i313 trained over a correspondingpulley lb on the armature shaft of a motor lib. The motor is attached tothe fork @5b by means of a suitable bracket llb. IThus, it will be seen,that the rubber tired wheel 19h is in frictional driving engagement withthe upper edge of one of the vertical walls of the launder E85 so as todrive the rake arm 22h in much the same manner as the propellers 22(Figs. l to 5 inclusive), and the friction wheel 5 lc (Fig, 6)

In the modified form of the invention shown in Figure 9 the liquid tank5c is identical in construction to that shown in Figures 1 to 5, and isprovided with a peripheral launder ISC for collecting the overflowliquid in a clarified lcondition and discharging it. The rake arm 22o isprovided with a forked extension Ello having an axle shaft Bic forsupporting a friction driving wheel 32e. A drive pulley 83o has its hubaflixed to the shaft 8 lc and is adapted to be driven by means of a belt5to drivingly connected to an electric motor (not shown) mounted on therake arm 22o. The fricti-on wheel 52 rotates about a vertical axis andin frictional driving engagement with the inner peripheral wall of thetank 5.

Referring to the Figure of the drawings, there is shown a wiring circuitfor the system wherein the electrical conductors is are provided forsupplying the pair of electric motors fi! with electrical energy from asuitable source of supply. Connected in parallel with the motors il isan overload relay 85 and an underload relay 58. When the load on theelectric motors is increased, the current drawn by that motor increasesproportionally. Thus, when the motors ill are overloaded, the relay 35is actuated thereby supplying electrical energy to the motor 53 throughcontacts Sl, 8s, and terminal dil, thereby causing the pump 5i toexhaust fluid from the ballast tank until the relay S5 is cle-energizedby the return of a normal load on the motors di. In the case of anunderloa-d, the relay is energized permitting the flow of currentthrough contacts 8?, Si?, and terminal tl, thereby allowing the motor 53to drive the pump 5l until a normal load is again reached. It is to benoted that the motor 53 is of the reversible type so that when currentis supplied through terminal lll the motor rotates in one direction, andwhen the current is supplied to terminal 95, rotation is caused in theopposite direction.

I claim:

l. In a liquid separation and purifying apparatus, a circular tankhaving a bottom wall sloping towards a center sediment removal trough,radially extending rake arms mounted in said tank so as to rotate aboutthe center of the tank, arcuately shaped agitator rake members on saidrake arms transversely thereof for directing sludge and sediment towardthe center of said tank into the said sediment removal trough, a floatmember for said rake arms for supporting said rake members variousdistances from the bottom wall of said tank, a frame hinged at the endof the rake arms next to the center of the tank in parallel relation tosaid rake arms, a

scraper element on the inner end of each frame at an angle thereto, aplurality of wiper elements carried by each of said frames inwardly ofthe scraper element, means connected to each of said frames to limit thedownward movement of said frames, a launder at the outer periphery ofthe tank providing a circular marginal pathway about the tank, and meansfixed to the outer ends of the rake arms and ooacting with said pathwayfor the rotation of saidradial rake arms.

2. In a liquid separation and purifying apparatus as in claim 1, theprovision of motor units on the outer ends of said rake arms foroperating the means for causing the rotation of said rake arms and meansis provided for varying the ballast in said float member to cause saidrake arms to assume different positions with respect to the slopingsurface of said bottom wall.

3. In a liquid separation and purifying apparatus as in claim 1 whereinthe said marginal pathway comprises the peripheral wall of the tank andthe means engaging the pathway for the rotation of said rake armscomprises a friction driving wheel in driving engagement with saidperipheral wall and a motor for driving said frice tion wheel and saidmotor and friction wheel are loatingly mounted on said rake arms to compensate for the various positions of the said rake arms.

4. In a liquid separation and purifying apparatus as in claim 1 whereina round vertical support is mounted in the center of the tank, and saidfloat member is annular in cross section and encircles the said support,rollers carried by said support engageable with the inner peripheralsurface of said annular float member to center said float member, pumpmeans for supplying liquid ballast to said float to vary the heightthereof above the bottom wall of said tank, and said circular pathway isprovided by the overflow liquid in said launder and impellers aremounted on the outer ends of said rake arms for engagement with saidliquid to cause the rotation of said rake arms.

5. In a liquid separation and purifying apparatus as in claim 1, whereina round vertical support is mounted in the center of said tank, and saidfloat member is of annular form and encircles the said support, rollersare carried by said support and are engageable with the inner peripheralsurface of said annular float member to center said float member in thetank, pump means are provided for supplying ballast liquid to said floatto vary the height thereof above the bottom wall of the tank, a motor ismounted on the outer end of each of said arms and a yieldingly mountedfriction driving wheel is mounted on the outer end of each of said rakearms, and the said marginal pathway comprises the peripheral wall ofsaid tank and said driving wheel is in frictional driving engagementwith said peripheral wall.

PAUL AIVIE CURTIS.

REFERENCES CITED rThe following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 20,761 Pruss June 14, 19381,356,608 Dorr Oct. 26, 1920 1,734,044 Orr Nov. 5, 1929 1,972,584Easterday Sept. 4, 1934 2,141,133 Gibbs Dec, 20, 1938

